This invention relates to packing, more particularly packing used to seal valve stems and the like.
A variety of packings are known for use in, e.g., a packing gland to seal valve stems exposed to high temperature and high pressure conditions. In the past, asbestos has been a packing of choice; however, due to environmental and health concerns, substitutes for asbestos have been sought. One substitute, described in U.S. Pat. No. 4,705,722, is composed of superimposed flexible graphite sheets, each having a width of less than 5mm, that are covered by knitting or braiding with a wire or fiber to form a knitting yarn or thread. The knitting yarns are twisted or braided to form the gland packing. Thereafter, the exposed wire or fiber on the surface is removed.